Re: Compression of full-page-writes

On Fri, Aug 30, 2013 at 2:32 PM, KONDO Mitsumasa
<kondo(dot)mitsumasa(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> (2013/08/30 11:55), Fujii Masao wrote:
>>
>> * Benchmark
>> pgbench -c 32 -j 4 -T 900 -M prepared
>> scaling factor: 100
>>
>> checkpoint_segments = 1024
>> checkpoint_timeout = 5min
>> (every checkpoint during benchmark were triggered by
>> checkpoint_timeout)
>
> Did you execute munual checkpoint before starting benchmark?

Yes.

> We read only your message, it occuered three times checkpoint during
> benchmark.
> But if you did not executed manual checkpoint, it would be different.
>
> You had better clear this point for more transparent evaluation.

What I executed was:

-------------------------------------
CHECKPOINT
SELECT pg_current_xlog_location()
pgbench -c 32 -j 4 -T 900 -M prepared -r -P 10
SELECT pg_current_xlog_location()
SELECT pg_xlog_location_diff() -- calculate the diff of the above locations
-------------------------------------

I repeated this several times to eliminate the noise.

Regards,

--
Fujii Masao